Usually, enabling fake I/O means there will be benchmark running on the system. However, a lot of messages are printed to the console:

Sep 17 05:50:49 es200nv2-vm1 kernel: systemd-journald[690]: /dev/kmsg buffer overrun, some messages lost.
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***
Sep 17 05:50:49 es200nv2-vm1 kernel: Lustre: *** cfs_fail_loc=238, val=0***

This is annoying, because a lot of CPU resource will be used by message printing.